.nav li {float: left;width: 100px;height: 20px;margin: 2px;list-style:none;text-align: center;}
.mid p {text-align: center;}
#p1 {font-size: 56px;line-height: 15px;font-weight: bold;}
#p2 {font-size: 24px;line-height: 15px;}
.nav a {text-decoration: none;color: white;font-weight: bold;font-size: 20px;}
.nav {width: 100%;height: 60px;background-color: rgba(0,0,0,0.1);position:fixed;top:0;left: 0;}
.mid {margin-top: 300px;}
.help {margin: 90px 30px;}
.help #help_p1 {font-size: 24px;line-height: 34px;}
.help #help_p2 {font-size: 20px;line-height: 36px;}
.intro0 {margin-top: 100px;}
.intro0 .intro1 {width: 65%;display: inline-block;margin-left: 50px;}
.intro0 .intro1 p {font-size: 20px;}
.intro0 .intro2 {width: 25%;display: inline-block;margin: 50px 0;}
.intro_end p {font-size: 14px;text-align: center;}